This invention generally relates to a radar system and method for determining the location of a target and more specifically to a radar system and method for passively determining the location of a target using jammer echoes.
One problem facing surveillance and fire control radar systems today is target detection and estimation of target angle in the presence of severe jamming interference. Typically, jamming is in the form of a high power transmission designed to impair a radar system""s performance. Jamming may comprise a signal modulated with noise or other disruptive information. The object of typical jammers is to impair the performance of a radar system""s receiving electronics and/or obscure the display of potential targets of interest. The source of jamming interference may be mobile or may be relatively stationary (e.g., land based systems).
In an attempt to avoid detection by surveillance and tracking radar systems, low observable (LO) platforms, such as aircraft and ships, utilize an obscuring medium such as a coating that reduces the amplitude of signals reflected from the platform. From the perspective of the radar system, it becomes even more difficult to detect an LO target in the presence of jamming interference. To improve its ability to detect an LO target in the presence of jamming, a radar system may increase its transmission power in an attempt to receive a stronger return signal or echo (indicative of the reflected signals). However, it is advantageous, in some circumstances, for the radar system to remain covert (no transmission). Thus, there is a need for a radar system and method for covertly detecting and tracking a target of interest, such as an LO target, in the presence of jamming.
A radar system and method for detecting a target of interest in the presence of a source of interference, wherein the source of interference emits interfering signals, includes a receiver for receiving the interfering signals directly from the source of interference. The receiver also receives reflected signals, wherein the reflected signals are the interfering signals reflected by the target of interest. The interfering signals and the reflected signals are compared to detect the target of interest.